1. Field of the Invention
The present invention relates to a printed wiring board and its manufacturing method. A printed wiring board of the present invention includes a core substrate having a penetrating hole made up of a first opening portion and a second opening portion, first circuit and second circuits formed on the core substrate, and a through-hole conductor formed in the penetrating hole and connecting the first and second circuits.
2. Discussion of the Background
Japanese Laid-Open Patent Publication 2006-41463 describes forming a penetrating hole made up of a first blind hole and a second blind hole in a dielectric layer. The penetrating hole in Japanese Laid-Open Patent Publication 2006-41463 is formed as an hourglass and is filled with conductive material. The contents of this publication are incorporated herein by reference in their entirety.